This invention relates generally to radio frequency array antenna structures and methods for fabricating such structures.
As is known in the art, it is generally highly desirable to provide light weight inexpensively fabricated radio frequency array antenna structures. According to this invention such an array antenna structure is provided by forming, on one or more relatively flexible dielectric sheets, a plurality of radio frequency circuits comprising a radiating array face of an array antenna and feed networks and then bonding such dielectric sheet (or sheets) to a suitable core material to form a complete array antenna structure which is light in weight, is inexpensive to fabricate and is structurally sound.
In one embodiment a planar array antenna is fabricated by using two dielectric sheets. One of such dielectric sheets has a conductive ground plane formed on one side and a plurality of corporate feed networks formed on the other side; the other one of such dielectric sheets has a plurality of annular slots etched from a ground plane formed on one side thereof. The two dielectric sheets are bonded together to form a stripline structure with the corporate feed networks on the one and annular slots on the other being in registry to form the radiating elements of the desired array antenna. The bonded dielectric sheets are then bonded to at least one stiffener (or core) to provide the desired completed array antenna.
In a second embodiment a conformal array is formed by arranging a plurality of array modules side-by-side around a predetermined conformal surface. Each one of the array modules includes a flexible dielectric sheet (or substrate) having simultaneously formed thereon circuitry which comprises an array of radiating elements, a ground plane for such elements, a corporate feed network and a portion of a parallel plate lens coupled to the feed network. The dielectric substrate with the circuitry formed thereon is folded around, and bonded to, a suitably shaped core to provide structure integrity to each array module.